Now that SetDrive is a complete command, the web/CAT Drive handler moves into
TWebAdapter.OnDrive (the one handler WA1 left behind). CAT context SetDriveLevel
repointed to it too.
Makes the channel-power-clear reactive: ChannelController.OnDriveChanged fires on
the rfDrive event and clears FPreChannelPower for any external drive change
(slider/web/encoder), guarded by FRestoringDrive for the unit's own apply/restore.
This removes the imperative ClearPreChannelPower coupling so SetDrive callers need
no channel knowledge.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Channels are recall-of-saved-config — a client of the radio core, not part
of DSP/network. Move ApplyChannel/CheckChannelActive + active-channel state
(FActiveChannelIdx, FPreChannelPower) out of MainForm into TChannelController,
which orchestrates controller commands and emits OnActiveChanged for the
Channel-button render. Removes the last UI-held state blocking headless mode.
Also completes TRadioController.SetDrive (was a skeleton): clamp + CalcDriveByte
+ SetDriveLevel + PushNetworkState + Changed(rfDrive), with an rfDrive render
case; routes slider/web/channel drive through it. Adds SetCurrentBandIdx for the
lightweight HF band switch.
Behavior note: channel recall now applies the mode-default filter via SetMode
(was: kept current filter — a latent quirk that left FM on an SSB bandwidth).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
